Posh Scandinavian lacking education (5)
I believe the answer is:
swish
'posh' is the definition.
(swish can mean posh or fancy)
'scandinavian lacking education' is the wordplay.
'scandinavian' becomes 'swedish' (Sweden is in Scandinavia).
'lacking' is a deletion indicator.
'education' becomes 'ed' (abbreviation - e.g. sex ed).
'swedish' with 'ed' taken away is 'SWISH'.
(Other definitions for swish that I've seen before include "Extravagant" , "Smart; stylish" , "Sound of cane" , "Stylish (sl.)" , "Elegant" .)